本文实例讲述了C#实现的上传图片、保存图片、加水印、生成缩略图功能。分享给大家供大家参考，具体如下：
伴随移动设备地普及，处理图片、视频等需求也变得越来越基础，这里介绍的是图片的存储。
上传图片必须使用form表单提交的方式，我只知道这一种方法，如果大家知道其他方法的话请留言。
保存图片、加水印和生成缩略图这三种功能最好各自放在单独的方法中，尽量降低耦合度，提高代码复用程度，除此之外我们平常写代码是也要尽量做到方法功能的唯一性。
前台代码：
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<form method="POST" enctype="multipart/form-data" action="UploadImg.ashx"> <table> <tr> <td>func：</td> <td><input type="text" name="func"/></td> </tr> <tr> <td>用户Id：</td> <td><input type="text" name="userId"/></td> </tr> <tr> <td>头像：</td> <td><input type="file" name="icon"/></td> </tr> <tr> <td>水印：</td> <td><input type="text" name="waterMark"/></td> </tr> </table> <input type="submit" value="提交"/></form> |
后台代码：
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private string UploadImage(HttpContext context){ try { System.IO.Stream stream = context.Request.Files["icon"].InputStream; //返回的图片路径可以存储在数据库中 string imageUrl = SaveImage(stream, "Icon", "蝈蝈"); string thumbnailImageUrl = SaveThumbnailImage(stream, "Icon"); string thumbnailImageUrlWithWatermark = SaveThumbnailImage(ConfigurationManager.AppSettings["AttachmentsDirectory"] + imageUrl, "Icon"); return "上传成功！"; } catch (Exception ex) { return "上传失败！"; }}private string SaveImage(Stream stream, string folderName, string waterMark){ try { string fileName = Guid.NewGuid() + ".jpg"; string path = ConfigurationManager.AppSettings["AttachmentsDirectory"]; path = Path.Combine(path, folderName + "\\" + DateTime.Now.Year + "\\" + DateTime.Now.Month + "\\" + DateTime.Now.Day + "\\"); string imageUrl = "/" + folderName + "/" + DateTime.Now.Year + "/" + DateTime.Now.Month + "/" + DateTime.Now.Day + "/"; if (!string.IsNullOrEmpty(waterMark)) { Image imgSource = Image.FromStream(stream); AddWatermarkAndSave(path, fileName, waterMark, imgSource, imgSource.Height - 300, 10, Color.Red, new Font("宋体", 40)); } else { byte[] buffer = new byte[stream.Length]; stream.Read(buffer, 0, buffer.Length); if (!Directory.Exists(path)) { Directory.CreateDirectory(path); } System.IO.FileStream fs = new System.IO.FileStream(path + fileName, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.Write); fs.Write(buffer, 0, buffer.Length); fs.Flush(); fs.Close(); } return imageUrl + fileName; } catch (Exception ex) { return ""; }}private string SaveThumbnailImage(Stream stream, string folderName){ try { string fileName = Guid.NewGuid() + ".jpg"; string path = ConfigurationManager.AppSettings["AttachmentsDirectory"]; path = Path.Combine(path, folderName + "\\" + DateTime.Now.Year + "\\" + DateTime.Now.Month + "\\" + DateTime.Now.Day + "\\"); string imageUrl = "/" + folderName + "/" + DateTime.Now.Year + "/" + DateTime.Now.Month + "/" + DateTime.Now.Day + "/"; System.Drawing.Image.GetThumbnailImageAbort myCallback = new System.Drawing.Image.GetThumbnailImageAbort(GetFalse); //数据源来自Stream Image image = System.Drawing.Bitmap.FromStream(stream); System.Drawing.Image thumbnailImage = image.GetThumbnailImage(64, 64, myCallback, IntPtr.Zero); thumbnailImage.Save(path + fileName); thumbnailImage.Dispose(); return imageUrl + fileName; } catch (Exception ex) { return ""; }}private string SaveThumbnailImage(string originalFileName, string folderName){ try { string fileName = Guid.NewGuid() + ".jpg"; string path = ConfigurationManager.AppSettings["AttachmentsDirectory"]; path = Path.Combine(path, folderName + "\\" + DateTime.Now.Year + "\\" + DateTime.Now.Month + "\\" + DateTime.Now.Day + "\\"); string imageUrl = "/" + folderName + "/" + DateTime.Now.Year + "/" + DateTime.Now.Month + "/" + DateTime.Now.Day + "/"; System.Drawing.Image.GetThumbnailImageAbort myCallback = new System.Drawing.Image.GetThumbnailImageAbort(GetFalse); //数据源来自File Image image = System.Drawing.Bitmap.FromFile(originalFileName); System.Drawing.Image thumbnailImage = image.GetThumbnailImage(64, 64, myCallback, IntPtr.Zero); thumbnailImage.Save(path + fileName); thumbnailImage.Dispose(); return imageUrl + fileName; } catch (Exception ex) { return ""; }}private bool GetFalse(){ return false;}/// <summary>/// 图片加文字水印/// </summary>/// <param name="fileName"> </param>/// <param name="text">水印文字，如果是多行用分号隔开</param>/// <param name="img">图片</param>/// <param name="paddingTop">上边距</param>/// <param name="paddingLeft">左边距</param>/// <param name="textColor">文字颜色</param>/// <param name="textFont">字体</param>/// <param name="path">保存地址</param>/// <returns></returns>private bool AddWatermarkAndSave(string path, string fileName, string text, Image img, int paddingTop, int paddingLeft, Color textColor, Font textFont){ text = text + ";" + "当前时间：" + DateTime.Now.ToString("yyyy-MM-dd HH:mm"); if (!Directory.Exists(path)) { Directory.CreateDirectory(path); } textFont = new Font("宋体", 19); Bitmap bm = new Bitmap(img); System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bm); System.Drawing.Brush b = new SolidBrush(textColor); string[] str = text.Split(';'); for (int i = 0; i < str.Length; i++) g.DrawString(str[i], textFont, b, paddingLeft, paddingTop + 33 * i); g.Dispose(); bm.Save(path + fileName, ImageFormat.Jpeg); bm.Dispose(); return true;} |
希望本文所述对大家C#程序设计有所帮助。
原文链接：https://blog.csdn.net/xiaouncle/article/details/54883327
